Process for the production of facings of pressed cork for rollers, drums, pulleys and the like



G. BALDAUF 1,984,625 PROCESS FOR THE PRODUCTION OF FACINGS OF PRESSED CORK Dec. 18, 1934.

FOR ROLLERS PULLEYS, AND THE LIKE 2 Sheets-Sheet 1 DRUMS Filed April 16, 1932 Fig. 6

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Dec. 18, 1934. G. BALDAUF 1,984,625

PROCESS FOR THE PRODUCTION OF FACINGS OF PRESSED CORK FOR ROLLERS, DRUMS, PULLEYS, AND'THE LIKE Filed April' 16, 1932 2 Sheets-Sheet 2 E' .9 1 1 .10 0 1\ r l 2? H 4 6 ig /n ventor:

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v Patented Dec. 18, 1934 PATENT OFFICE PROCESS FOR THE PRODUCTION OF FAC- INGS F PRESSED CORK FOR. ROLLERS, DRUMS, PULLEYS AND THE LIKE Gustav Baldauf, Munich, Germany Application April 16, 1932, Serial No. 605,715 In Germany November 17, 1931 8 Claims. (Cl. 19-143) The presentinvention relates to facings of pressed cork for rollers, drums, pulleys and the like and the production thereof.

It is known, that cork on account of its elastic properties is used as facings for rollers, drums, pulleys and the like to promote adhesion.

Facings'of this kind are mostly made of pressed cork placed in the form of strips around the object to be faced.

It will be convenient for the purposes of comparing the former processes with that the subject of the present invention to refer now to the accompanying sheets of drawings, in which:--

Fig. 1 is a perspective view of a pressed cork block showing a strip split therefrom in a direction perpendicular to the direction in which the block was pressed. Fig. 2 is a similar perspective view of a pressed cork block showing a strip split therefrom in a direction parallel to the direction in which the block was pressed.

Fig. 3 shows a roller faced with a strip cut as shown in Fig. l, the facing being shown in section at the top of the figure.

Fig. 4 shows a .roller faced with a strip cut as shown in Fig. 2, the facing being shown in section at the top of the figure.

Fig. 5 is a perspective view of a pressed cork block showing how according to the present invention strips are obliquely out therefrom.

Fig. 6 shows a roller faced with a strip cut asshown in Fig. 5, the facing being shown in section at the top of the figure.

Fig. '7 illustrates how the stripmay be spirally wound on the roller, and

Fig. 8 shows a section of the faced roller on the line XX of Fig. 7.

Fig. 9 shows, diagrammatically and thecreti-' cally, an enlargement of the cork facing according to Fig. 3, the facing being shown in section at the top of the figure.

Fig. 10 shows, diagrammatically and theoretically, an enlargement of the cork facing according to Fig. 4, the facing being shown in section at the top of the figure.

Fig. 11 shows, diagrammatically and theoretically, an enlargement of the cork facing according to Fig. 6;"the facing being shown in section at the top of the figure.

Fig. 12 shows, diagrammatically and theoretically, an enlargement of the cork facing according to Figs. 7, the facing being shown in section at the top of the figure.

Hitherto the strips of pressed cork have been cut out of blocks of cork, which for the purpose of producing the pressed cork were pressed in the direction indicated by the arrow A in Fig. l. The strips were split to the desired thicknesses out of these blocks 1 either in a direction B perpendicular to the direction of pressure A shown in Fig. 1, or in a direction D parallel to the direction of pressure A as shown in Fig. 2 and then cut to the required width and length.

Entire bodies were also cut out of these small blocks of pressed cork either perpendicular or parallel to the direction of pressure and fashioned into cylindrical forms which were then mounted on the cores of the rollers or pulleys.

In accordance with these known processes, cork facings were produced which vary in structure. A cork facing produced on the lines shown in Fig. 1 is illustrated in Fig. 3. The cork material, which was compressed in the direction of A in Fig. 1, now lies in the direction of C perpendicularly pressed to the axis GG of the roller. The individual particles of cork of practically difierent form lie flatly pressed on the circumference of the roller and are not rooted together in the depth thereof. This is open to the objection that individual small plates of cork 3, shown in cross section at the top and in elevation below in Figs. 3 and 9 are liable to break away. This defect is apparent not only when the surface of the cork pieces is being ground down, but also when in actual use, and leads to rapid wear and tear of the cork facing, and also results, in the case, for example, of conveyor rollers for fibrous material, in fibrous material remaining suspended in the recesses in. the surface between the small plates of cork 3 and at those places from which the cork plates 3 have broken away.

The facings obtained in the manner shown in Fig. 2, in which the cork material was cut in the direction of D, produce when mounted on the core of a roller a facing, a cross section of which is shown at the top and an elevation below in Fig. ,4, and for explanation on a larger scale in Fig. 10, and in which the small cork plates 3 are pressed in a direction H parallel to the-axis G-G of the roller. This form of construction is open to the objection that the stratification of the cork particles 3 that are compressed in the axial direction G-G lies in the direction of motion of the material that is to be carried along, apart from which the cork material when Stratified in this way loses a great deal of its elasticity, because the flatly compressed cork particles are more heavily strained in the direction of its maximum moment of resistance, also cork layers 3 and binding intermediate layers 4 alternate in this form of construction, and in consequence grooves are liable to be formed, which necessitate frequent grinding. In the unavoidable breaking away of ticles 3 respectively 11, 22 etc., according to the method of preparing the facings as shown byFig. 2 and Fig. 4, in which the compression is parallel to the roller axis.

' With this arrangement the pressure of the fibrous material along the line P tends to open the junctions between the cork particles 11 and 22 in the direction 1', 1' and the fibrous material is liable to be trapped therein. Also the elasticity at diiferent places of the outer face is liable to vary according as to whether the pressure of thefibrous material is along the line P at a junction or along the line P 'of the cork ele- The object aimed at in the present invention is the production of facings of pressed cork forrollers, drums, pulleys and the like that overcomes these defects.

In accordance with this invention as illustrated in Fig. 5, there are cut out of the block of pressed cork 1 that is pressed in the known way in thedirection of the arrow A, strips K in such a manner that the cut surface of these strips K lies at an acute angle or preferably of something between 15 and 30 degrees to the direction of pressure A. In this way, a cork material is obtained whose surface is composed of obliquely out small platesof cork 5. Owing to this slanting out each thoroughly pressed cork plate 5 exhibits an 'oval surface. If, as shown in Fig. 6, a cork strip of this kind be laid on the periphery of a roller or of a pulley, the individual elements of which the cork is composed lie obliquely to the axis GG of the roller as shown in cross section a at the top in Fig. 6. The surface of the coatin results in a smoother surface, whose finestructure mitigates the defects of the facings shown in Figs. 3 and4.

Owing to the slanting out, the surfaces with which the particles of cork are pressed together, as shown at the top of Fig. 6 and on a'larger scale in Fig. 11 at the top, lie obliquely to the axis of the roller. It will be seen from the diagrammatic and theoretical illustration Fig. 11, that a fibre running .over the facing in the line of pressure P will not find a trapping joint in the line of pressure. Its pressure is exerted substantially on the cork particle-22 whence it is communicated to the particle 33. In this way an advantage is obtained, more particularly in the case of facingsfor conveyor rollers for fibrous material, for example for the calenderrollers inthe manufacture of textiles, because underneath the work piece and perpendicular to the axis of the roller, the fibres and threads do not find any trapping grooves. running in their direction of pressure and cannot consequently work readily into such grooves and adhere thereto.

Moreover, the elasticity of facings made under the present invention'is of an increased order relatively to the form of construction shown in Fig. 4, since the particles of cork 5 lie obliquely to the axis G-G of the roller, whilst the load of them is'applied through the work piece perpendicularly to the axis G--G.

From the upper part of the illustration Fig. 11 it will be seen that the pressure of a fibre which is exerted in the direction P is no longer exerted in the direction of a trapping joint, but upon the particle 22, which elastically is assisted by the particle 33 and underlying particles.

Such elastic working is also of a like order whether the line of pressure of a fibre is directed in the direction P at a junction or in the direction P on a cork particle. In this way the present invention realizes a practical uniform elasticity at all points of the outer surface of the facing.

In the same way, facings of this kind can also be obtained from a block of pressed cork, by cutting out small blocks at an angle to the direction of pressure, grinding and boring them out, or by cutting cylinders out of the material of which the block is composed obliquely to its direction of pressure A.

The facings can be produced in a very con venient way as follows. The strip K cut out at an acute angle a from the block 1 shown in Fig. 5 has a parallelogramlike cross section. Strips K of any desired width can be obtained according to the height of the block 1 and to the size of the angle a. When the strips K which are cut parallel to one another are placed in one and the same position one against the other, the slopes will fit one another. If very long strips of cork are needed, the ends S of the individual strips K can be joined together by someadhesive. If, as shown in Fig. 7, the strips K be now wound spirally on a mandrel and an adhesive applied, atubular facing will be obtained which owing to its obliquely lying course 0 exhibits great strength and firm binding.

In the case of facings for conveyor rollers for fibrous material the advantage afforded by the fact that the particles of cork lie obliquely to the axis of the roller is still more enhanced.

As shown in Fig. 7 and the theoretical illustration Fig. 12, by the spiral arrangement, the cork particles 11, 22, 33, etc., are disposed in a direction inclined to the axis 6-6 and the facing exhibits the advantage already described with as a result of the spiral winding the cork particles also become inclined in a direction t to a plane perpendicular to the axis G-G of the hollow cylinder, whereby its upper surface is composed of small cork surfaces which are inclined to the direction of movement of the fibres, so that a double safeguard is afforded against the fibres and'threads working into'its structure.

Any desired thickness, strength and compactness of tube can also be obtained by winding several layers of cork strips one over the other with successive courses displaced with respect to-each other to break joint. To meet special. requirements, layers for instance of woven material, paper or metal can also be interwound with the strips of cork or may serve as inner core below the cork layer.

It will be-found particularly advantageous to bake the completed tubes or rings at a temperature of at least 180 degrees C., as is done in cork factories, and thus obtain a product that is very compact and resistant to heat, moisture and the growth of microbes. The baking process must be such that the products wound with cork material are placed under pressure in an exactly fitting mould surrounding the cork material on all sides, and baked. At a temperature of not less than 180 degrees 0., the cork endeavours to expand, that is to say, the cork walls of the air cells are loosened and owing to their natural expansion and to the increased volume, i. e. increased pressure of the contents of the air cells, the cork'body endeavours to swell. Since it has however been pressed intoa firm mould, the individual particles of cork press closely against each other and against the mould surrounding the cork mass on all sides. Owing to the internal pressure of the air cells, the cork elements are shattered or split into minute particles as the air contained in the cells escapes. The final product obtained by this process is a coating of particularly great compactness offering a high resistance to compression and having a velvety-smooth surface.

I claim:

1. The process of producing cork facings for rollers and the like which comprises compressing cork particles into a block with the pressure applied all in one definite direction, thereupon cutting slices from said block in a direction oblique to that of the applied pressure, and forming said slices into the facings.

2. The process of producing cork facings for rollers and the like which comprises compressing cork particles into a block with the pressure applied all in one definite direction, thereupon cutting thin slices from said block in a direction oblique to that of the said applied pressure, winding said slices spirally and pasting them into a tube.

3. The process of producing cork facings for roller-sand thelike which comprises compressing cork particles into a block with the pressure applied all in one definite direction, thereupon cutting thin slices from said block in a direction oblique to that of the said applied pressure, winding and pasting said slices around the core of said rollers and the like.

4. The process of producing cork facings for rollers and the like which comprises compressing cork particles into a block with the pressure applied all in one definite direction, thereupon cutting slices from' said block in a direction oblique .01. the compacting pressure, thereupon cutting slices from said block in a direction oblique to that of the applied compacting pressure, assembling said slices by spirally winding the same into a hollow tube, and thereupon compressing said tube under heat in a mold.

6. The process as defined in claim 5, wherein the temperature employed in the molding operation is in excess of 180 C.

7. The improvement in a cork facing for rollers and the like, which comprises compacted cork particles, these particles being pressed into a block with the pressure applied all in one direction, and said facing being cut from said block in a direction oblique to that of the applied pressure.

8. The improvement in a cylindrical. cork facing for rollers and the like, which comprises a helically wound layer of compacted cork particles, these particles being pressed into a block with the pressure applied all in one direction, and said layer being cut from said block in a direction oblique to that of the applied pressure.

GUSTAV BALDAUF. 

